When I was a girl, John 1:1 was my favorite verse. An odd choice for a child, but I loved the sound of it, and the circle that it made. "In the beginning was the Word, and the Word was with God, and the Word was God."
Studying the Bible is always a good idea, and the first chapter of John is a great starting place. Some resources to start you on your journey, while heeding the admonition to "lean not on your own understanding." Pv. 3:5.
I thought a sample of the richness of the doctors of the Church might be in order.
St. John Chrystostom, Homilies on the Gospel of St. John
St. Augustine, Tractates on the Gospel of St. John
St. Thomas Aquinas, Commentary on the Gospel of St. John
Biblia Clerus' repository of commentary on the Gospel of St. John
John 1:29 says "The next day John seeth Jesus coming unto him, and saith, Behold the Lamb of God, which taketh away the sin of the world."
Candy's note on John 1:29: Jesus takes away the sins of anyone who will let Him. There is nothing else one must do to be saved. Jesus paid it all. Jesus is our perfect sacrificial Lamb, whose sacrifice pays for ALL of our sins. In the Old Testament, lambs and other animals had to be sacrificed on a regular basis, to atone for sins. God Himself, as Jesus Christ, became the perfect sacrificial Lamb, to pay for our sins.
The note to John 1:29 in my Navarre Bible Reader's Edition:
For the first time in the Gospel Christ is called the "Lamb of God". Isaiah had compared the sufferings of the Servant of Yahweh, the Messiah, with the sacrifice of a lamb (cf. Is 53:7); and the blood of the paschal lamb smeared on the doors of houses had served to protect the first-born of the Israelites in Egypt (cf. Ex 12:6-7): all this was a promise and prefiguring of the true Lamb, Christ, the victim in the sacrifice of Calvary on behalf of all mankind. This is why St. Paul will say that "Christ, our paschal lamb, has been sacrificed" (1 Cor 5:7). The expression "Lamb of God" also suggests the spotless innocence of the Redeemer (cf. 1 Pet 1:18-20; 1 Jn 3:5).
The sacred text says "the sin of the world", in the singular, to make it absolutely clear that every kind of sin is taken away: Christ came to free us from original sin, which in Adam affected all men, and from all personal sins.
The book of Revelation reveals to us that Jesus is victorious and glorious in heaven as the slain lamb (cf. Rev 5:6-14), surrounded by saints, martyrs and virgins (Rev 7:9, 14; 14:1-5), who render him the praise and glory due him as God (Rev 7:10). Since Holy Communion is a sharing in the sacrifice of Christ, priests say these words of the Baptist before administering it, to encourage the faithful to be grateful to our Lord for giving himself up to death to sve us and for giving himself to us as nourishment for our souls.